Morphological and mechanical characterization of reinforcement in cracked elements exposed to chloride-induced corrosion

In Reinforced Concrete (RC) structures exposed to chloride-rich environments, reinforcement corrosion might be already initiated (especially at crack location). A deep knowledge on the correlation between the mechanical properties of corroded bars and corrosive attack morphology, useful for the evaluation of the residual bearing capacity of structure, is still lacking. In this paper, morphological and mechanical characterization of steel reinforcement embedded in RC specimens (with and without fibers) both in cracked stage and subjected to cyclic exposure to a 5 % NaCl solution for 280 days was carried out. Although a chloride content higher than the critical chloride threshold was also measured in correspondence of uncracked concrete, corrosive attacks were observed only in correspondence of cracks. Pits were mostly characterized by a shallow morphology, which led to a rebar diameter loss ranging between 1 and 10 %. Furthermore, the results showed that both yielding and ultimate load of corroded rebars can be predicted by combining circular residual cross-section and mechanical properties of uncorroded rebars.